Transmission control switch



April 10, 1951 J. H. EISENMANN 2,548,145

TRANSMISSION CONTROL SWITCH Filed March 17, 194e 2 Sheets-Sheet l April l0, 1951 J. H. EISENMANN 2,548,145

TRANSMISSION CONTROL SWITCH Filed March 17, 1349 2 Sheets-Sheet 2 Patented Apr. 10, 1951 TRANSMISSION CONTROL SWITCH John H. Eisenmann, Detroit, Mich., assignor to Chrysler Corporation, Highland Park, Mich., a

corporation of Delaware Application March 17, 1949, Serial N0. 81,973

8 Claims.

This invention relates to a transmission control mechanism for an automotive vehicle and more particularly to means to control the initiation of a change in transmission speed ratio drive.

Thisrinvention is an improvement on the device described and claimed in the copending application of Thomas M. Ball, Serial No. 71,871, led January 21, 1949.

Reference will be made herein to a relatively fast speed drive which is usually the cruising drive for a vehicle. This may, for example, be a one to one driving speed ratio known as a direct drive or an overdrive. Reference will also be made to a relatively slow speed drive which is a vehicle accelerating speed ratio drive and may be a torque multiplying drive r where an overdrive is provided for the relatively fast speed drive the relatively slow speed drive may be a direct drive. The term kickdown, as used herein, refers to a downshift or step-down in the transmission as, for example, a downshift from the relatively fast speed drive to the relatively slow speed drive.

In automotive vehicles having automatic controls associated with variable speed ratio transmissions it has been found desirable to provide means responsive Ato control by the operator for reverting to a relatively slow speed drive when theoperator is confronted with an emergency demanding fast acceleration. Such means have usually included a solenoid actuator and controls therefor including a switch which is arranged to cooperate with the engine carburetor throttle control mechanism so as to cause a change in speed ratio drive of the vehicle when the usual accelerator pedal is depressed to a predetermined position. It has also been found with such arrangements that under certain conditions as where the vehicle is traveling at a comparatively high rate of speed the transmission cannot be safely operated in a relatively slow speed drive as above described due to the excessive engine speed which would be required. Means have heretofore been provided for limiting the operation of such controls to those engine and vehicle speeds in which a relatively slow speed drive may be safely accommodated.

t is an object of this invention to provide a control for a variable speed ratio transmission by means of which a solenoid actuator associated with the transmission may be actuated to effect a change in transmission speed ratio drive by positioning the throttle control linkage in a predeter mined position and to associate with this control a means to maintain the condition of the control so'established after the throttle controllinkage 2 has retracted from the above predetermined position. The speed ratio drive effected by the solenoid is thus maintained after the throttle Control linkage has been moved from the above predetermined position.

It is a principal object of this invention to provide a means by winch the device of the copending Ball application Serial No. 71,871 or its equivalent may be adjusted so that the unlatching of the switch will occur at the optimum throttle position. This permits the kickdown switch to be unlatched at a time coinciding with a selected angular position of the throttle blade.

The transmission illustrated and described in Patent No. 2,348,763 issued on May 16, 1944, to A. J. Syrovy et al. and the copending application, Serial No. 374,674 of Neracher et al. are examples of transmissions to which the controls to be described herein may be applied.

In the trawings:

Fig. l is a diagrammatic View showing a portion of Van automotive engine including a carburetor and a power transmission with the present invention applied thereto;

Fig. 2 is an enlarged sectional view illustrating the control mechanism applied to the carburetor shown in Fig. 1; a portion of the carburetor being broken away;

Fig. 3 is a side elevation of the carburetor and control of Fig. 1;

Fig. 4 is a partial elevation of the device illus-V trated in Fig. 3;

Fig. 5 is a section taken on the line 5 5 of Fig. 4;

Fig. 6 is an exploded view of the adjustable cam element;

Fig. 7 is a perspective view of a portion of the switch latching mechanism showing a modified form of yadjusting means; and

Fig. 8 is a section taken on the line 8 8 of Fig. '7.

Certain abbreviated terminology will be adopted herein to facilitate the description of the invention. The means associated with the throttle control linkage and which is adapted to cause a relatively slow speed drive to be effected will be hereinatfer referred to as a kickdown control, The means which limits the operation of the kickdown control to certain engine and vehicle speeds will be referred to as an upper limit control,

Y It is apparent that the control described herein should be associated with some manipulation of the throttle linkage which will signal the oper' ators desire for an vupshift and yet permit some latitude of vehicle operation with respect toen- "gine speed during the relatively slow speed drive. The control, therefore, should be designed to initiate an upshift as the throttle is brought towards a throttle closing position beyond the lower limit of throttle opening that would normally be desired in the operation of the vehicle in its relatively slow speed drive.

The numeral lil generally indicates an internal combustion engine having an intake manifold l2 on which is mounted a carburetor ld. The carburetor is provided with a conventional throttle valve l5 (Fig. 3) which is adapted to be manipulated by movement of an accelerator pedal I6. rEhe pedal le is yieldably urged to its throttle closing position by a spring i3. Pedal it which is pivotally mounted at 26 has linkage operatively connected thereto for remote control of the throttie and this linkage is indicated by the numerals 22, 24, 26, 28 and shaft 3l).

A variable speed ratio transmission has been generally indicated by the numeral 32 and is positioned rearwardly of the engine i@ and adapted to transmit drive from the engine lo to a propeller shaft (not shown). U. S. Patent No. 2,348,763 and copending application, Serial No. 374,674, illustrate transmissions which could be controlled by the apparatus to be described herein. A solenoid vactuator 34, illustrated as mounted on the side of the transmission 32, may be associated with` the transmission control apparatus so that energization of the solenoid actuator 34 will effect a kickdown or downshift of the transmission to a relatively slowl speed drive. Deenergization of the solenoid actuator 34 may be utilized to efiect an upshift of the transmission to a relatively fast speed drive.

In Fig. l a typical circuit with which my invention may be associated for the control of the energization of solenoid actuator 3d has been illustrated as including a vehicle storage battery 35 which is grounded at 3S. battery includes a conductor 35 connecting the battery to the solenoid actuator Sil, a conductor 3'! connecting solenoid actuator 34 to a grounded vehicle speed responsivegovernor d3 having terminals and #i5 and switch means 39 to electrically connect these terminals when the vehicle speed is less than a predetermined value. The circuit also includes a grounded kickdown control switch ft2 incorporating my invention and connected by a conductor lll to the conductor 3l so that the governor switch 39 and kickdown switch d2 are in parallel. The switches 29 and t2 are each operable when closed to ground the circuit. The governor 43 may be of any suitable design whioh is operatively connected to a rdriven portion of the transmission or other vehicle speed responsive members.

Operation of the kickdown control to be discussed herein is limited to those occasions on which the predetermined vehicle speed controlling the governor 43 has been exceeded so thai the terminals lll) and 45are not electrically connected. A kickdown control is not necessary below this predetermined speed as the governor switch 39 provides an energization of solenoid actuator 3d and a relatively slow speed drive.

l The kickdown control switch 42 is illustrated in detail in Figure 2. An electrical conductor 4 i, previously referred to, is connected with a rst conductor terminal 44 which is electrically insulated at 46 from the supporting carburetor parts. A movable contacting conductor 48 of silver or other suitable material, is connected to 'and extends ldownwardly from a piston 53. The

rThe circuit from the conductor llt is free from engagement with the first terminal lll prior to operation of the kickdown control mechanism as hereinafter described. Conductor i8 is sufficiently resilient so that it can be flexed into contact with the terminal iid and will assume its Figure 2 position again when the parts are in position as shown.

The piston Eli which is the movable portion of the upper limit control previously referred to is free to slide in a cylinder 52 and is urged downwardly therein by a spring 54 until the piston engages the insulation 56. The upper end of the piston is open to receive the spring 54 and the interior of cylinder 52 is connected by a passage 5t to the engine intake at the atmospheric side of the throttle valve l5 so that the piston 5l] is always subjected to the vacuum existing on the atmospheric side of the throttle valve. It is preferable if the passage E is connected to the throat of the conventional carburetor venturi (not shown).

The spring 5ft yieldably urges the piston 50 downwardly to the position illustrated in Figure 2 to position the contact [i8 in line with the fixed terminal lll for engagement therewith under the influence of the control mechanism unless the vacuum in the intake and passage 56 is sufficient to withdraw piston 5l) and contact 48 upwardly out of alignment with the terminal 44.

Means are provided herein which are responsive to operation of the throttle control mechanism during a portion of its throttle opening movement and preferably during that portion thereof when the accelerator pedal I6 is brought to its fully depressed position corresponding to approximately full open position of the throttle valve l5, or an overtravel of the pedal beyond the full open throttle valve position, to ground the conductor 44 through contact 48. A plungerlike member 65) is slidably mounted in a cylinder 52 formed in the housing of switch 42. A second plunger-like member 64 is slidably received in a bore 65 provided in member 6D. The members 69 and 54 are retained against relative separation in an axial direction by an enlarged portion 68 o the member 64 cooperating with an inwardly directed flange 7U carried by the member 6D. The members @il and 64 are yieldably urged to their Figure 2 position by a relatively heavy spring l2 which is positioned in cylinder 52. A spring 76 interposed directly between the members SEB and 61% urges the enlarged portion of the member 6d to the left as viewed in Figure 2 against the flange 70 of the member St. The lever 28 which forms a part of the linkage connecting the accelerator pedal with the throttle valve, and which was previously referred to, is illustrated in Figure 3 as provided with an extension Bil adapted to contact the exterior end of member @il when the pedal is depressed so that the throttle valve l5 is in substantially Wide open throttle position. If desired, the contact of extension Si@ with plate F4 may be adjusted to Aoccur in response to an overtravel of the pedal i6 beyond full open throttle position. In either event the extension SG applies an axial force tending to move the member 6U to the left in Fig. 2 in response to contact of these parts. This movement occurs against the opposition of spring l2 and the plunger like member 64 is yieldably forced to the left in Fig. 2 by spring 'i6 until it iiexes the contact terminal i8 into contact with the terminal M. The conductor di is thus grounded through-dll, 48; 64 and .the

parts within the bore 62 which are in electrical connection with the carburetor casing.

When, however, the vacuum on the atmospheric side of the throttle valve is suflicient to draw the piston 5i) upwardly against the force of the spring 54 and thereby dispose the contact 48 out of alignment with the terminal 44 depression of the accelerator pedal I6 as aforesaid will not result in formation of the grounded electric circuit for the parts are so arranged that the plunger like member 64 does not have suficient stroke under such circumstance to engage the terminal 44. A suitable stop 'I8 in the form of a shoulder on the switch housing is provided to limit the movement of the members 60 and B4.

Kickdown switches and upper limit control switches generally are recognized as devices heretofore employed in the art. However, in certain transmissions it is desirable to provide means for retaining the member 64, contact 48 and terminal 44 in electrical contact after the accelerator pedal I6 has initiated a kickdown and subsequently been retracted to a more modified throttle opening position. Therefore, it is desirable to provide a reduced end portion 82 on the member t0. This construction provides a shoulder 84 so located with respect to the axis of the member E0 that it comes substantially in the plane of the external surface of the switch housing when the member 60 is moved to the left by the extension 88 of throttle control linkage 28. A plate 8B, which is adapted to cooperate with the shoulder 84, is pivotally mounted at 88 on the exterior of the switch housing in a plane normal to the axis of the member 6B. The plate 86 is provided with a slot 90 and a screw 92 extends through the slot and is secured to the switch housing. The arcuate slot 90 serves as a guide for pivotal movement of the plate 86 in the plane transverse to the axis of member G. The plate S6 is also provided with an opening 94 which is preferably located between the pivot 88 and the slot 9S. The opening 94 has a diameter greater than the diameter of the larger extended portion of member B8 so that the axial movement referred to may be accommodated by movement of member 50 through the opening S4. The member 69 and the switch housing are preferably provided with cooperating shoulders 96 and 98 which limit the extent of movement of member 60 to the right as shown in Fig. 2. A spring |80 is positioned to react between plate 8S and the switch housing to normally urge the plate 86 to pivot or rotate in a clockwise direction in Fig. 4. It will be seen that this normally does not impair movement of member 6u until the shoulder 84 passes through the opening 94, at which time the clockwise movement of plate 86 under the influence of spring |88 causes the member 60 to be locked in position. This position corresponds to the extreme position assumed during its movement to the left in Fig. 2. This movement occurs under the infiuence of member 28 of the throttle control linkage and the shoulder 84 is so positioned that it passes through the opening 94 at the time when the member E4 is in contact with the contact 43 and the latter is in contact with the contact 44. The switch components are thus retained in the switch on position irrespective of subsequent movements of the throttle linkage.

In order to provide a means for opening the switch when an upshift is desired the lever 28 'of the throttle controllinkage is provided with an extension |02 having a cam element |04 secured thereto which is adapted to engage a portion of plate 86 when the throttle control linkage is retracted to a predetermined position. This predetermined position is preferably a position corresponding to a substantially closed throttle condition. The cam element |04 induces a counterclockwise rotation of plate B as an incident to retraction of the throttle control linkage. Sufficient counterclockwise rotation of plate 86 will realign opening 94 with the larger extended portion of member 8i] so that the member 60 may extend through the opening 94 and be moved to the right in Fig. 2 under the influence of spring l2 until shoulders Q6 and 98 engage thereby interrupting the electrical circuit, deenergizing solenoid actuator 34 and inducing .ari upshift in the transmission speed ratio drive. It is assumed of course that the governor switch is open at this time for it is only under these conditions that an operator would require the switch 4.2 to initiate an upshift. The extension |82 is provided lwith a table portion |56 which projects at right angles from extension |52 and is preferably curved on an arc having the throttle shaft 35 axis at its center (see Fig. 3). The cam element i313 is provided with a cooperating curved p-ortion |88 which rests on and is secured to table portion |08. Portion |08 has a slot H0 which extends lengthwise thereof and table portion |06 is provided with a pair of threaded openings ||2. A pair of screws l |4 penetrate slot H8 and are received within threaded openings |42. The cam element it is formed with a cam surface having an extended portion H6 adapted to engage a portion of plate 86 to rotate the latter about its pivotal mounting at 88. The slot H8 accommodates selective positioning of the cam element |84 relative to the extension |02. The screws H4 provide a. means for securing the cam element in its selected position. Variations in the positioning of the cam element |84 on the extension |82 vary the relationship between the position of the throttie valve |5 and the unlatching of the switch 42;

A modified form of the invention is illustrated in Figs. 7 and 8. In this form of the invention thehead of a screw |29 is substituted for the cam element lli and the plate 86 is provided with a lug |22 positioned to be engaged by the screw head |2il. The screw i2@ is selectively positioned in an arcuate slot |21 provided on a portion |26 of lever 28 and retained in any selected position by a conventional nut and lock washer illustrated in Fig. 8. When the throttle valve I5 is return-ed to its throttle closed position the screw |2t contacts the lug |22 to rotate plate 86 in a counterclockwise direction and release the switch as previously described. It is evident from referring to Fig. 7 that the position in the slot |24 selected for the screw |20 will determine the relationship between throttle position and switch unlatching.

I claim: y

1. A control for an electrical circuit of a motor vehicle having a throttle valve and linkage operable to control the position of saidV throttle valve, said control including a switch having a shiftable contact operable to selectively energize and deenergize said circuit, means associated with said linkage and operable to move said Contact to close said switch and energize said circuit as an incident to movement of said linkage beyond a predetermined limit in a direction tending to open the vehicle throttle, means to lock said switch contact in its closed position, a cam carried by said linkage and mounted for adjustment ther-ecn relative to said last mentioned means and operable to engage said last-mentioned means and release said switch contact as an incident to the return of said linkage to a second predetermined position.

2. An adjustable control for an electrical circuit of a motor vehicle having a throttle and linkage operable to control the throttle; said control including a switch having a member movable to first and second positions with one of said positions electing an electrical closing of said switch, spacing means urging said member to one of said positions, means associated with the motor vehicle throttle control linkage and operable to move said member t0 the other of said positions as an incident to movement of said linkage beyond a iirst predetermined position, locking means operable to retain said member in one of said positions, and cam means carried by said throttle control linkage and mounted for adjustment thereon relative to said locking means and operable to release said locking means as an incident to movement of said linkage beyond a second position determined by the adjustment of said cam means.

3. A control for an electrical circuit of a motor vehicle having a throttle and linkage operable to control the throttle; said control including a switch having a movable m-ember, means associated with the motor vehicle throttle control linkage and operable to move said member to a switch closing position as an incident to movement oi said linkage beyond a predetermined limit in a direction tending to open the vehicle throttle, an element rotatably mounted on said switch, spring means urging said element to rotate in a rst direction, cam means carried. by said throttle control linkage and mounted for adjustment thereon relative to said element and operable to rotate said element in a second direction as an incident to movement of said linkage beyond a second position in a direction tending to close said throttle, the adjustment of said cam means selectively determining said second position and said member being provided with a surface adapted to be engaged by said element when the latter is rotated in its rst direction and said member is in its switch closing position to lock said member in its switch closing position until released by said cam means.

4. An adjustable control for an electrical circuit of a motor vehicle having a throttle and link- 'age operable to control the throttle; said control including a switch having a me-mber movable to rst and second positions with one of said positions effecting an electrical closing of said switch, spring means urging said member to one of said positions, means associated with the motor vehicle throttle control linkage and operable to move said member to the other of said positions as an incident to movement of said linkage beyond a rst predetermined position, locking means operable to retain said member in one of said positions, a ca-m element having an elongated slot therein and screw means penetrating said slot and adjustably securingsaid cam element to said linkage, said cam element being adapted to release said locking means as an incident to movement of said linkage beyond a second predetermined position.

5. An adjustable control for an electrical circuit of a motor vehicle having a throttle and linkage operable to control the throttle; said control including a switch having a member movable to first and second positions with one of said positions effecting an electrical closing of said switch, spring means urging said member to one of said positions, means associated with the motor vehicle throttle control linkage and operable to move said member to the other of said positions as an incident to movement of said linkage beyond a first predetermined position, locking means operable to retain said member in one of said positions, said linkage including a rotatable arm having an arcuate table portion, a cam element having a cooperating arcuate portion provided with an elongated slot therein, said arcuate portions having their center of curvature coinciding with the axis of rotation of said arm, screw means penetrating Said slot and adjustably securing said cam element to said linkage, said cam element being adapted to release said locking means as an incident to movement of said linkage beyond a second predetermined position.

6. An adjustable control for an electrical circuit of a motor vehicle having a throttle and linkage operable to control the throttle; said control including a switch having a member movable to first and second positions with one of said positions effecting an electrical closing of said switch, spring means urging said member to one 0f Said positions, means associated with the motor vehicle throttle control linkage and operable to move said member to the other of said positions as an incident to movement of said linkage beyond a rst predetermined position, locking means operable to retain said member in one of said positions, said linkage including a rotatable arm, a cam element, screw means, and means forming a slot adapted to cooperate with said screw means to secure said cam element to said arm, said slot facilitating adjustment of said cam element relative to said arm and said locking means and said cam element being adapted to release said locking means as an incident to movement of said linkage beyond a second predetermined position.

'7. An adjustable control for an electrical circuit of a motor vehicle having a throttle and linkage operable to control the throttle; said control including a switch having a member movable to rst and second positions with one of said positions effecting an electrical closing of said switch, spring means urging said member to one of said positions, means associated with the motor vehicle throttle control linkage and operable to move said member to the other of said positions as an incident to movement of said linkage be- `yond a rst predetermined position, locking means operable to retain said member in one of said positions, said linkage including a rotatable arm having a slot therein, a screw penetrating said slot and having a head thereon adapted to serve as a cam element, releasable means to secure said screw to said arm so that the position of said head relative to said arm and said locking means may be altered, said cam element being adapted to release said locking means as an incident to movement of said linkage beyond a second predetermined position.

8. A control for an electrical circuit of a motor vehicle having a throttle valve and linkage operable to control the position of said throttle valve, said control including a switch having a shiftable contact operable to selectively energize and deenergize said circuit, means associated with said linkage and operable to move said contact to close said switch and energize said circuit as an incident to movement of said linkage beyond a predetermined limit in a .direction tending to 9 l0 open the 'vehicle throttle, an element mounted REFERENCES CITED for movement and operable 1n one position to The following references are of record in the lock said switch Contact 1n its closed posltion, cofue of this partent: operating cam elements carried by said element and said linkage respectively and operable to cam 5 UNITED STATES PATENTS said element away from said one position to re- Number Name Date lease said switch Contact when said linkage is 1,944,084 Hutt Jan. 16, 1934 moved to a predetermined position and means 2,396,551 Boyce Mar. 12, 1946 mounting one of said cam elements for adjustn ment relative to the other cam element to thereby 10 preselect said predetermined position.

JOHN H. EISENMANN. 

